feat!: add CIDVersion type

[achingbrain]

Enables us to constrain CID version to 0 | 1, similar to how we used to do with the cids module.

[rvagg]

Any reason to think this might be a breaking change for downstream users? Will it break TS compiles in any way (presuming they're only using 0 or 1 - outside of that it's their own fault).

[achingbrain]

I think it is breaking as the argument type for several functions has been constrained from number to 0|1 - it'll break anyone passing variable with the number type into CID.create (for example) but not if they are passing a literal 1 or 0.

This should be ok:

function foo (/* maybe some args here */) {
  const version = 1

  // other code here

  return CID.create(version, /* other args here */)
}

But this will not be:

function bar (version: number, /* maybe some args here */) {
  // other code here
 
  return CID.create(version, /* other args here */)
}

[rvagg]

ok then, let's do the semver dance again